Numerical Simulation for Droplet Combustion Using Lagrangian Hydrodynamics

A predictive model of spray combustion must incorporate models for the wide variety of physical environments in a practical combustor. In regions where droplets are closely spaced, combustion resembles a diffusion flame; where they are well separated, an envelope or wake flame results. The relative velocity field between the fuel droplets and oxidizer in influences boundary layer development about the droplet, recirculating flow patterns, and droplet shape and stability. A model must encompass these interacting temporal and spatial effects as well as complicated combustor boundaries. The objective of the current work is to develop the triangular gridding method for describing the individual and collective properties of vaporizing and burning fuel droplets

Numerical simulations of fuel droplet flows using a Lagrangian triangular mesh

The incompressible, Lagrangian, triangular grid code, SPLISH, was converted for the study of flows in and around fuel droplets. This involved developing, testing and incorporating algorithms for surface tension and viscosity. The major features of the Lagrangian method and the algorithms are described. Benchmarks of the algorithms are given. Several calculations are presented for kerosene droplets in air. Finally, extensions which make the code compressible and three dimensional are discussed

Mind the implementation gap?:Police reform and local policing in the Netherlands and Scotland

In 2013 the governments of the Netherlands and Scotland established national police forces, replacing a tradition of largely autonomous regional police organizations. In both jurisdictions, these radical reforms have raised concerns about the consequences of these national police structures for local policing and for relationships with local communities and local government. Drawing on documentary sources and interview material from each jurisdiction and informed by insights from the policy implementation literature, the key question addressed in this article is how has the legislation that created the new national police forces been put into effect at a local level? Focusing on the impact on the governance, organization and delivery of local policing, the article reveals how the implementation in both jurisdictions involves interpretation and discretion by multiple actors so that gaps are emerging between the national ‘policy promises’ set out in the legislation and the ‘policy products’ experienced in local contexts

Manifold Elastic Net: A Unified Framework for Sparse Dimension Reduction

It is difficult to find the optimal sparse solution of a manifold learning based dimensionality reduction algorithm. The lasso or the elastic net penalized manifold learning based dimensionality reduction is not directly a lasso penalized least square problem and thus the least angle regression (LARS) (Efron et al. \cite{LARS}), one of the most popular algorithms in sparse learning, cannot be applied. Therefore, most current approaches take indirect ways or have strict settings, which can be inconvenient for applications. In this paper, we proposed the manifold elastic net or MEN for short. MEN incorporates the merits of both the manifold learning based dimensionality reduction and the sparse learning based dimensionality reduction. By using a series of equivalent transformations, we show MEN is equivalent to the lasso penalized least square problem and thus LARS is adopted to obtain the optimal sparse solution of MEN. In particular, MEN has the following advantages for subsequent classification: 1) the local geometry of samples is well preserved for low dimensional data representation, 2) both the margin maximization and the classification error minimization are considered for sparse projection calculation, 3) the projection matrix of MEN improves the parsimony in computation, 4) the elastic net penalty reduces the over-fitting problem, and 5) the projection matrix of MEN can be interpreted psychologically and physiologically. Experimental evidence on face recognition over various popular datasets suggests that MEN is superior to top level dimensionality reduction algorithms.Comment: 33 pages, 12 figure

Effects of cooperation on information disclosure in mock‐witness interviews

Purpose: Forensic interviewers often face witnesses who are unwilling to cooperate with the investigation. In this experimental study, we examined the extent to which cooperativeness instructions affect information disclosure in a witness investigative interview. Methods: One hundred and thirty-six participants watched a recorded mock-crime and were interviewed twice as mock-witnesses. They were randomly assigned to one of four conditions instructing different levels of cooperativeness: Control (no instructions), Cooperation, No Cooperation, and No Cooperation plus Cooperation. The cooperativeness instructions aimed to influence how participants’ perceived the costs and benefits of cooperation. We predicted that Cooperation and No Cooperation instructions would increase and decrease information disclosure and accuracy, respectively. Results: We found decreased information disclosure and, to a lesser extent, accuracy in the No Cooperation and No Cooperation plus Cooperation conditions. In a second interview, the shift of instructions from No Cooperation to Cooperation led to a limited increase of information disclosure at no cost of accuracy. Cooperativeness instructions partially influenced the communication strategies participants used to disclose or withhold information. Conclusions: Our results demonstrate the detrimental effects of uncooperativeness on information disclosure and, to a lesser extent, the accuracy of witness statements. We discuss the implications of a lack of witness cooperation and the importance of gaining witness cooperation to facilitate information disclosure in investigative interviews

Ferredoxin containing bacteriocins suggest a novel mechanism of iron uptake in <i>Pectobacterium spp</i>

In order to kill competing strains of the same or closely related bacterial species, many bacteria produce potent narrow-spectrum protein antibiotics known as bacteriocins. Two sequenced strains of the phytopathogenic bacterium &lt;i&gt;Pectobacterium carotovorum&lt;/i&gt; carry genes encoding putative bacteriocins which have seemingly evolved through a recombination event to encode proteins containing an N-terminal domain with extensive similarity to a [2Fe-2S] plant ferredoxin and a C-terminal colicin M-like catalytic domain. In this work, we show that these genes encode active bacteriocins, pectocin M1 and M2, which target strains of &lt;i&gt;Pectobacterium carotovorum&lt;/i&gt; and &lt;i&gt;Pectobacterium atrosepticum&lt;/i&gt; with increased potency under iron limiting conditions. The activity of pectocin M1 and M2 can be inhibited by the addition of spinach ferredoxin, indicating that the ferredoxin domain of these proteins acts as a receptor binding domain. This effect is not observed with the mammalian ferredoxin protein adrenodoxin, indicating that &lt;i&gt;Pectobacterium spp.&lt;/i&gt; carries a specific receptor for plant ferredoxins and that these plant pathogens may acquire iron from the host through the uptake of ferredoxin. In further support of this hypothesis we show that the growth of strains of &lt;i&gt;Pectobacterium carotovorum&lt;/i&gt; and &lt;i&gt;atrosepticum&lt;/i&gt; that are not sensitive to the cytotoxic effects of pectocin M1 is enhanced in the presence of pectocin M1 and M2 under iron limiting conditions. A similar growth enhancement under iron limiting conditions is observed with spinach ferrodoxin, but not with adrenodoxin. Our data indicate that pectocin M1 and M2 have evolved to parasitise an existing iron uptake pathway by using a ferredoxin-containing receptor binding domain as a Trojan horse to gain entry into susceptible cells

A window into land managers’ preferences for new forms of agri-environmental schemes: Evidence from a post-Brexit analysis

Securing the provision of environmental public goods from agriculture is central to addressing the critical challenge of ensuring global food security while halting ecosystem degradation. Agri-environment schemes (AES) are considered to have a key role to play in supporting the transition to more sustainable ways of producing food. Existing evidence suggests that farmers are generally willing to enrol in AES for the delivery of environmental features, but robust policy support requires further exploration of land managers’ preferences and how these interplay with contract features to achieve higher environmental targets. We undertook a discrete choice experiment with land managers in post-Brexit UK, with what can be considered a ‘benchmark’ sample of younger AES-inclined land managers. This provides a window into the future of the UK farming landscape, but also, given the revision of the European Union’s Common Agricultural Policy and other international discussions, it also provides insights into land managers’ preferences for new contract features more widely. Our results suggest that (such type of) land managers are likely to be receptive to a transition to result-based, collaborative schemes supporting landscape-wide interventions in alignment with net zero agendas. These interventions could be done in exchange for levels of compensation similar to current levels. While this raises promise, our results also emphasize challenges, particularly to attract those less generally AES-prone land managers. Payments levels probably need to remain close to the current ones (not lower), farmers’ awareness and support for net-zero agendas need to be reinforced and more interaction between land managers and policy makers will be needed

Volcanic Contribution to Decadal Changes in Tropospheric Temperature

Despite continued growth in atmospheric levels of greenhouse gases, global mean surface and tropospheric temperatures have shown slower warming since 1998 than previously. Possible explanations for the slow-down include internal climate variability, external cooling influences and observational errors. Several recent modelling studies have examined the contribution of early twenty-first-century volcanic eruptions to the muted surface warming. Here we present a detailed analysis of the impact of recent volcanic forcing on tropospheric temperature, based on observations as well as climate model simulations. We identify statistically significant correlations between observations of stratospheric aerosol optical depth and satellite-based estimates of both tropospheric temperature and short-wave fluxes at the top of the atmosphere. We show that climate model simulations without the effects of early twenty-first-century volcanic eruptions overestimate the tropospheric warming observed since 1998. In two simulations with more realistic volcanic influences following the 1991 Pinatubo eruption, differences between simulated and observed tropospheric temperature trends over the period 1998 to 2012 are up to 15% smaller, with large uncertainties in the magnitude of the effect. To reduce these uncertainties, better observations of eruption-specific properties of volcanic aerosols are needed, as well as improved representation of these eruption-specific properties in climate model simulations

Revisiting Southern Hemisphere polar stratospheric temperature trends in WACCM: The role of dynamical forcing

The latest version of the Whole Atmosphere Community Climate Model (WACCM), which includes a new chemistry scheme and an updated parameterization of orographic gravity waves, produces temperature trends in the Antarctic lower stratosphere in excellent agreement with radiosonde observations for 1969-1998 as regards magnitude, location, timing, and persistence. The maximum trend, reached in November at 100hPa, is -4.42.8Kdecade(-1), which is a third smaller than the largest trend in the previous version of WACCM. Comparison with a simulation without the updated orographic gravity wave parameterization, together with analysis of the model's thermodynamic budget, reveals that the reduced trend is due to the effects of a stronger Brewer-Dobson circulation in the new simulations, which warms the polar cap. The effects are both direct (a trend in adiabatic warming in late spring) and indirect (a smaller trend in ozone, hence a smaller reduction in shortwave heating, due to the warmer environment)